----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----
Hi Kevin,
I don't think anyone intended to suggest using "...the the wrong hose
on a fitting...". These days, many of us might assume that the AN 840
type
"pipe thread" fittings were what was fitted to the Ercoupe, since the part
where the engine compartment flexible hoses attach is identical.
In actuality, it's pretty hard to pick a "wrong hose". All the Ercoupe
Parts Catalog calls out is an interior "size" and length. The suction and
pressure lines to and from the fuel pump are called out as "1/4", and the
one from the firewall to the Gascolator is called out as "3/8".
Since (") is not part of the (official) description, it would seem these
(1/4 and 3/8) are nominal sizes. 303-4 hose (for 1/4" tubes) is actually
3/16" i.d. and 303-6 (for 3/8" tubes) is actually 5/16" i.d. per my
catalog
information. You want a proper line-to-fitting seal BEFORE tightening the
clamp. There should be further dimensional and descriptive information on
drawing 415-48201 (if anyone has a copy for reference).
Almost any hose made today is superior in useful life, pressure capability
and fuel resistance to that originally specified (Resistoflex?).
MIL-H-6000
and DTL6000C hoses are specifically designed for push-on fittings (like
the
Ercoupe's) and they are rated to 1,000 lbs. pressure (definately
overkill)!
I believe exterior stainless braid hoses retain integrity a bit longer in
a
fire than rubber/cotten fibre hoses, but you won't see it (or screw-on
fittings) if you cover it with Firesleeve!
Regards,
WRB
---------------------------------------
on 04/30/04 8:12 PM, Kevin Gassert at [EMAIL PROTECTED] wrote:
> I am not sure what bothers me the most, the suggestion to use the wrong
hose
> on a fitting or no one speaking up on the dangers of this action.
>
> Kevin
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Sent: Wednesday, April 28, 2004 8:57 PM
> To: ercoupe tech
> Subject: [COUPERS-TECH] more on fuel hoses
>
> ----[Please read http://ercoupers.com/disclaimer.htm before following
any
> advice in this forum.]----
>
>
> OK. I am going to send this only to the tech list, since we have been
asked
> to refrain from "double posting".
>
> Since I started the fuel hose thread I think I should add to it as well.
>
> I was wondering how many people are using fuel and oil hoses with metal
> pipe-thread ends, and how many are still using the push on type, secured
> by hose clamps.
>
> It seems to me that changing to the threaded ends means changing all my
> metal
> fuel line ends, which is real "pretzel" work.
>
> Thanks for the note about mil-h-6000 being changed to mil-dtl-6000. I
think
> that is where the confusion came from. I was worried that the change,
and
> the
> fact that it says "not recommended for fuel" was because of a material
> change
> in the hose. It appears that the note refers to the fact that most
modern
> aircraft use "finished" hoses with fittings, and that is probably what
most
> engineers would look for.
>
> The fact that the coupe was made with push-on ends probably leaves us in
the
>
> minority. However, it property installed, and coated with fire-sleeves,
I
> don't
> see why it wouldn't be just as safe.
>
> One problem with looking at other hoses is that the newer hoses are
lighter
> and
> are acually a smaller diameter for the same hose. For instance the -6
hose
> is
> actually an I.D. of .32 rather than .37. It might make it difficult to
push
> on
> the old fittings. The -8 hose is .41 ID and would probably work just as
well
>
> and be lighter in the long run. The same may hold true with the -4 hoses
for
> the fuel pump. You may have to go up one size to get it to fit the
fittings.
>
> Steve Finkelman
> C-FIWR
>
>
>
>
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